main: use /dev/urandom by default

Reading /dev/random blocks when the system doesn't have enough
entropy. Reading /dev/urandom doesn't block and is presumed to be
good enough for our purposes

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
pud: set local loopback for multicast tx

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Merge branch 'release-0.6.5'

* release-0.6.5:
  pud: set local loopback for multicast tx
  main: use /dev/urandom by default
arprefresh: fix some spelling

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
arprefresh: document the BPF program to make it readable

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
arprefresh: use the ARRAYSIZE macro

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
arprefresh: remove a comment

What is in the comment is already in the socket filter

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
arprefresh: do not process IPv6 packets when in IPv4 mode

Because the code assumes IPv4.

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
arprefresh: add a note about VLANs and IPv6

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
[hotfix] plugin: httpinfo: in case of an unrecoverable error ("could not initialize HTTP socket") exit for returnvalue != 0
plugin: dot_draw: readme: make it clear, that it only opens an IPv4-socket, so a 'telnet ::1 2004' is not possible
plugin: dot_draw: readme: replaced a b0rken link
mDNS: remove from Makefile PTHREAD useless dependency